we have a problem with our newsletter plugin.
Newsletter shows that it has sent, but it doesn’t reach the recipients. The test mail doesn’t arrive too.
If we delete the return path, the delivery of the test mail works. No matter what email address is entered as return path, again it doesn’t work.
Do you have any idea, how we could solve this problem?
We have the latest version of the newsletter plugin and automatic updates.
Thank you for your help!